Universal scanning mechanism for radar



p 7, 1954 w. o. LEWIS 2,688,70Q

UNIVERSAL SCANNING MECHANISM FOR RADAR Filed Sept. 7, 1946 4 Sheets-Sheet l 8:2 MMA 147' TORNE V Sept. 7, 1954 w. D. LEWIS 2,688,700

UNIVERSAL SCANNING MECHANISM FOR RADAR Filed Sept. 7, 1946 4 Sheets-Sheet 2 FIG? H as Q 29 .70

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kJ-IL I 7' [5/ %Lfl I U I"' T :1 m; I 1 /7 Y O l J as 3 19 3 J .37 5 l1 so 34 i L *J A J M ii .INVE/VTOR WDLLEW/f ATTORNEY Sept. 7, 1954 w. D. LEWIS 216889700 UNIVERSAL SCANNING MECHANISM FOR RADAR Filed Sept. 7, 1946 4 Sheets-Sheet 3 FIG. 3

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UNIVERSAL SCANNING MECHANISM FOR RADAR Filed Sept. 7, 1946 4 Sheets-Sheet 4 F IG. 5

FIG. 6A FIG. 0

FIG. 60 FIG. 6B

Patented Sept. 7, 1954 UNIVERSAL SCANNING MECHANISM FOR RADAR Willard D. Lewis, Little Silver, N. J assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 7, 1946, Serial No. 695,569

3 Claims.

This invention relates to electric wave reflectors and more particularly to a scanning mechanism for use in such electric wave reflectors.

The object of the present invention is the provision in an electric wave reflector of a scanning mechanism in which the feed horn is actuated in a manner to generate a plurality of scanning geometrical figures as determined by the speed relation of two independently operating eccentric mechanisms.

In the drawing, v

Fig. 1 is an assembly view showing the feed horn of the scanning mechanism positioned in coaxial relation to the longitudinal axis of its supporting eccentric shaft;

Fig. 2 is a view similar to that of Fig. 1 showing a number of operating parts in longitudinal section;

Fig. 3 is a front view of Fig. 1 shown with a number of operating parts with portions broken Fig. 4 is a cross-sectional View taken on line 44 of Fig. 2;

Fig. 5 is another front view shown with the feed horn 180 degrees from that shown in Fig. 3; and

Figs. 6A, 6B, 6C, 6D, and 6E are few examples of geometrical figures obtained by the change in speed relation of the eccentric mechanisms.

In the scanning mechanism of this invention, a casing serves for mounting a tubular shaft H formed at one end thereof with an eccentric hollow crank arm portion 28 and a hollow spindle portion 52, the spindle portion 12 being provided for rotatably mounting a section 26 of a two part casing which will be hereinafter described in detail.

On the tubular shaft I! is rotatably mounted as on ball bearings l3 and M, best seen in Figs. 2, 3 and 4, a drum-shaped member 15, the hub portion l6 of which is formed with an angle gear ll disposed in engagement with a similar gear l8 keyed on a hollow shaft 3| itself rotatably mounted as on ball bearing 39 fitted in the sleeve portion I?! of casing Ill, while the drum-shaped member 15 is supported at its peripheral edge portion by a ball bearing 20 fitted in casing I0 as best seen in Figs. 2 and and secured in adjusted position therein by a nut ring 5!. The drumshaped member IS in turn serves to support through the ball bearing I4 the front disposed end of hollow shaft II in position concentric to that of easing I0 While the opposite end of hollow shaft II is supported by a ball bearing 34 fitted into a counterbore 50 in the casing I0.

An internal gear 2| which is carried by the drum-shaped member l5 engages with a pinion 22 keyed or formed with the sleeve 23 of casing section 26 rotatably mounted as on ball bearings 24 and 25 carried by the eccentrically disposed spindle I2. To the casing section 26 is secured a complemental casing section 2! which includes the feed horn portion H to form in cooperation with the arm portion 33 formed by casing sections 26 and 21, the tubular eccentrically disposed spindle portion 12, the tubular arm portion 28 and the hollow shaft H, a portion of the wave guide, the casing section 21 being secured to casing section 26 by a plurality of screws 29 and a screw 30, the latter extending through a clearance hole in a counterweight portion W formed with casing section 21 in threaded engagement with a counterweight portion WI formed with casing section 26.

The counterweight elements W and WI serve to balance the arm portion 33 of the wave guide including the feed horn portion H while a counterweight W2 carried by the hollow shaft ll serves to balance the eccentric portion l2, casing sections 26, 21 and crank arm 28.

On shaft l l is keyed an angle gear 36 disposed in meshing engagement with a similar gear 31 keyed on one end of a shaft 38 rotatably mounted in the hollow shaft 3! itself rotatably supported by the ball bearing 39 fitted into the sleeve portion Ill of easing II].

In the operation of the scanning mechanism of the invention considering the hollow shaft H in a stationary condition, the rotation of gear ill on shaft 3| is effective to impart rotation to the drum-shaped member [5 to cause the rotation of the feed horn H on the eccentrically disposed spindle of hollow shaft H for generating a circle having for radius the distance from the center of feed horn H to the center of spindle l2. The rotation of hollow shaft ll considering the drum-shaped member l5 and internal gear 2| carried thereby in a stationary condition, is effective to cause the feed horn H to generate a planetary scanning movement around a circle the radius of which is that of the distance from the longitudinal axis of shaft H to the longitudinal axis of spindle l2, and from the axis of spindle E2 to the center of feed horn H while the operation of both the shaft H and drum-shaped member [5 as effected by shafts 38 and 3| is effective to generate for example a straight horizontal line as shown graphically in Fig. 6A, a straight vertical line shown in Fig. 63, a spiral as shown in Fig. 6C, a circle as shown in Fig. 6D,

an ellipse as shown in Fig. 6E and other figures depending upon the speed variation of shaft ll relative to the internal gear 2| and pinion 22 actuated thereby.

What is claimed is:

1. In a scanning mechanism comprising a casing, a pair of concentrically disposed drive shafts mounted for rotation in said casing, a driving gear keyed on each of said drive shafts within said casing, a tubular shaft mounted for rotation in said casing at right angles to said drive shafts, a drum-shaped member mounted for rotation on said tubular shaft, a gear carried by said drum-shaped member engaging one of said driving gears, a gear carried by said tubular shaft engaging the other of said driving gears, a crank element on the end of said tubular shaft within said drum-shaped member, said tubular shaft and said crank element forming a section of a wave guide, a horn-shaped scanning member for the wave guide mounted for eccentric rotation on said crank element, and separate driving mechanisms for rotating said tubular shaft and said horn-shaped scanning member for imparting scanning movements of different geometrical figures to the latter determined by the speeds of said separate driving mechanisms.

2. In a scanning mechanism a pair of independently operating driving shafts, a gear carried by each of said shafts, a pair of concentric hollow driven shafts each having a gear meshing with one of the first-mentioned gears, a drum-shaped member on one end of the outer of said concentric hollow driven shafts supporting a ring gear, a hollow crank formed on one end of the inner of said concentric hollow driven shafts within said drum-shaped member, a sleeve rotatably mounted on the handle portion of said crank and having a pinion meshing with said ring gear for rotating said sleeve, and a hollow horn-shaped scanning element on said sleeve and offset therefrom forming the receiving and transmitting end of a wave guide for said scanning mechanism, said horn-shaped scanning element together with said hollow crank and the inner of said drive shafts forming the wave guide for said mechanism.

3. In a scanning mechanism comprising a revolvable Wave-guide shaft, a hollow crank mounted on said shaft having a hollow handle portion forming a section of the wave guide for said apparatus, a sleeve mounted for rotation on said handle portion of said crank, a horn-shaped element forming the receiving and transmitting end of said wave guide carried by said sleeve, said sleeve having a pinion secured thereon, and a ring gear engaging said pinion mounted for movement concentric to the shaft of said crank for rotating said sleeve to impart eccentric planetary scanning movements to said horn-shaped element depending upon the speeds of rotation of said crank and said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 317,731 Colman May 12, 1885 1,167,336 Clark Jan. 4, 1916 1,264,128 Rataiczak et a1. Apr. 23, 1918 1,420,319 Kelly June 20, 1922 "2,410,827 Langstroth et a1. Nov. 12, 1946 FOREIGN PATENTS Number Country Date 298,599 "Germany Dec. 3, 1919 547.973 France Oct. 9, 1922 

